Jim
Grant's Tech TipsBelow is a collection of Jim Grant's Tech Tips sorted by Vehicle
Make. These Tech Tips were answers to questions submitted to Jim by ALLDATAdiy.com
users over the course of many years. If you have any questions,
please feel free to email
us.

Q:
I have a '96 Cadillac Sedan Deville with 175k miles. Recently, I have
been getting a service engine light and a service transmission message
while driving along at highway speed. The only effect that I can determine
is that I get a hard shift but the transmission works O.K. otherwise.
The problem clears after a few days of driving then reappears. Only once
has this occurred while the transmission was shifting. I cannot seem to
find anyone who has experienced this problem before. Have you had this
problem submitted to you and if so, what is the answer?

-
H.J. L.

A:The
transmission in your vehicle is computerized. From your description the
computer is not happy and wants some attention. When the computer loses
important information for operating the transmission a back-up program
is initiated. When this occurs the shifting becomes more pronounced (harsher),
gas mileage will drop, the check engine and on Cadillacs the service transmission
soon light will be turned on. Many repair shops just do not deal with
computerized transmission problems. Your best bet for a repair on your
Caddy is to go the dealer or an automatic transmission shop.